共查询到20条相似文献，搜索用时 0 毫秒
1.
D. Nestler H. Jung S. Arnold B. Wielage S. Nendel L. Kroll 《Materialwissenschaft und Werkstofftechnik》2014,45(6):531-536
Hybrid laminates combine the positive properties of the metal and fibre reinforced plastic (FRP) components. Advantages of the FRP, like formability, recyclability as well as suitability for mass production, provide an outstanding advantage over thermosetting matrices. For the production of the hybrid laminates, at first continuous fibers and thermoplastic films are pre‐consolidated to fibre‐reinforced unidirectional tapes. Subsequently, these are pressed together with the metal component in a loadcapable optimized arrangement. Thereby the interface between the FRP and the metal foils is of crucial importance. This paper focuses on hybrid laminates with carbon‐fiber reinforced polyamide (CF‐PA6) functioning as core layers and glass‐fiber reinforced polyamide (GF‐PA6) as intermediate layers between the centre and metal component. Laminates in 2/1 and 3/2 structure with two respectively three metal layers and one respectively two FRP layers are examined. For the metal foil, the aluminium alloy EN AW‐6082 and the titanium alloy Ti3Al2.5V (Grade 9) are used. The production of these laminates, development and adjustment of the interface and the evaluation of mechanical properties are investigated in this article. 相似文献
2.
This study aims to investigate the rheological and mechanical properties of polypropylene when reinforced by wood flour. In the study, wood flour (WF) was added as filling material to polypropylene (PP), and its effects were investigated. The grain size of the wood flour was 300 μm. Wood flour was mixed into polypropylene material at different rates of weight. Viscosity changes of the polypropylene at various temperatures and pressure values of the concentration rates were documented. As a result, viscosity increases as the amount of wood flour filling is increased; yet as temperature, pressure and shear rate are increased, viscosity decreases. The study also focuses on the changes in its mechanical properties of polypropylene reinforced with wood flour. The tensile strength of reinforced polypropylene at varying percentages (wt. 5 %, wt. 10 % and wt. 15 %) was observed to decrease by 11 %, 16 % and 21 %, respectively, compared to that of non‐reinforced polypropylene. Additionally, impact tests showed that the highest energy absorption was in 10 % wood flour reinforced polypropylene. 相似文献
3.
研究了Ultraviolet A(UVA)紫外辐射对碳纤维增强环氧树脂基复合材料产生的影响。测量和分析了从窗户照射到室内太阳光和日光灯辐射的UVA紫外线辐照度, 研究了碳纤维增强环氧树脂基复合材料经辐照度为200 μW·cm-2的UVA紫外灯辐射处理后的力学性能变化, 并通过XPS、 接触角、 纳米压痕、 原子力显微镜(AFM)测试方法研究了其表面性能变化。结果表明: 春夏季节晴天室内太阳光紫外辐照度在14点时达到最大值, 距离窗户0 m处最大值为375 μW·cm-2, 1 m处最大值迅速降至30 μW·cm-2; 对功率40 W的日光灯, 距离日光灯0 m处, 紫外辐照度为87.3 μW·cm-2, 1 m处快速降至5.4 μW·cm-2; 经过45天的紫外辐射, 碳纤维增强环氧树脂基复合材料的层间剪切强度、 弯曲强度和拉伸强度无明显变化; 碳纤维增强环氧树脂基复合材料表面发生氧化反应, 表面硬度和粗糙度变大。 相似文献
4.
The mechanical behaviour of fibre reinforced composites depends – amongst other things – on the morphological structure. This in turn is greatly affected by the processing conditions. In this study a 10 weight % flax fibre reinforced high density polyethylene composite is prepared by extrusion compounding followed by injection moulding. The effect of injection temperature, speed and rotational screw speed on the morphology of fibres and matrix are studied and related to the tensile and impact behaviour of the composites. Results indicate that fibre length is easily affected by all parameters under consideration. Whereas a higher injection temperature allows the preservation of fibre length, an excessive increase in temperature, however, leads to their thermal degradation. Increased injection and rotational speeds further introduce excessive shear stresses on the fibre, causing their breakage, similarly leading to reduced mechanical performance. Matrix structure is mainly affected by the injection temperature, where its increase leads to the reduction in the degree of crystallinity and thus also a decrease in tensile strength. Other processing parameters prove to have minor effect on matrix morphology. 相似文献
5.
The work‐hardening response and mechanical properties of dual phase steels originated from different initial microstructures under low and high martensite volume fractions were investigated using a typical carbon‐manganese steel. The modified Crussard‐Jaoul analysis was used for studying the work‐hardening stages and the deformation behavior of ferrite and martensite. It was revealed that the initial martensitic microstructure before intercritical annealing is much better than the full annealed banded ferritic‐pearlitic and spheroidized microstructures in terms of work‐hardening capacity and strength‐ductility trade off. By increasing the amount of martensite, via intercritical annealing at higher temperatures, the ductility decreased but the tensile toughness of dual phase steels increased toward reaching the domain of extra‐advanced high‐strength steels due to the enhancement of work‐hardening rate. 相似文献
6.
利用马来酸酐和丁基缩水甘油醚对超支化聚合物端基改性,得到以羧基和羟基为末端的超支化聚合物,其中和成盐后即得水性超支化聚合物(WHPs),通过红外光谱(FT-IR)和核磁共振(1H-NMR)对初始聚合物和改性聚合物的结构进行了表征。然后将WHPs应用于水性环氧涂料中,以差示扫描量热法对体系的固化行为进行了分析,研究了其固化动力学,并且研究了不同含量WHPs对体系固化涂层力学性能的影响。结果表明,该固化体系的表观活化能较低,固化反应容易进行,该WHPs的加入促进了体系固化反应,能够较好地改善涂膜的力学性能。当WHPs的加入量为10%时,涂层的综合力学性能达到最佳。 相似文献
7.
This paper focuses on the effects of heat treatment parameters on the microstructural and mechanical properties of quenchable 30MnB5 steel. Heat treatment parameters, such as different cooling media and different heating times at the same temperature, were investigated and compared. Tensile and hardness tests were performed at room temperature, and then the microstructures of the specimens were studied using optical microscopy and the results were compared. The results showed that boron steel heat treated using a water quenching process exhibited the best mechanical properties because of the formation of a martensitic microstructure. 相似文献
8.
9.
The microstructure and properties of chromium bronze, with different chromium content and treatment method, were characterized by using scanning electron microscope, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy and optical microscopy technique. For the specimens with the same treatment method, with increasing of the chromium content, the number of chromium phase increase and the dispersion strengthen effect enhances. On the other hand, the hinder effect on the electrons enhances and the electrical conductivity decreases. For the specimens with same component, the tensile strength and hardness order from low to high are: casting, aging treatment and solution aging. The electrical conductivity order from low to high are: casting, solution aging and aging treatment. 相似文献
10.
A. E. M. Hassan A. I. EiD M. El‐Sheikh W.Y. Ali 《Materialwissenschaft und Werkstofftechnik》2019,50(1):74-85
With polymeric nanocomposites many problems due to their extensive applications such as aerospace, automobiles, coatings, and packaging materials were solved. In this study, polyamide 12/graphene nanoplatelets impregnated by paraffin oil were fabricated by a hot compression technique. Elastic modulus has been determined by compression tests using a universal testing machine. Microhardness of unfilled polyamide 12 and its nanocomposites has been measured by Vickers microhardness testing machine. Tribological properties of the unfilled polyamide 12 and its nanocomposites have been investigated by pin‐on‐disc tester under applied normal loads of 10 N, 20 N and 30 N, 1.2 m/s sliding speed, and 212 m sliding distance. The results showed that the elastic modulus and microhardness of polyamide 12/graphene nanoplatelets (PA12/GNPs) nanocomposites are higher than that of the unfilled polyamide 12, and then gradually increased by adding paraffin oil contents. Tribological properties showed that polyamide 12/graphene nanoplatelets nanocomposites have lower coefficient of friction and wear rates in comparison with polyamide 12. By adding paraffin oil contents to the unfilled polyamide 12 and its nanocomposites, coefficient of friction and wear rates gradually decreased. Worn surfaces were imaged using scanning electron microscope. 相似文献
11.
M. Shaeri K.K. Taheri A.K. Taheri M.H. Shaeri 《Materialwissenschaft und Werkstofftechnik》2019,50(2):187-196
In order to optimize the aging treatment of Mg‐1.8Zn‐0.7Si‐0.4Ca alloy, different times and temperatures of solid solution and age hardening were applied to the alloy specimens. Microstructures and mechanical properties of the specimens were investigated using the optical microscopy, field emission scanning electron microscopy equipped with an energy dispersive x‐ray spectrometer, x‐ray diffraction, hardness, and shear punch tests. The lowest hardness and strength were achieved by solution treating of the alloy at 500 °C for 8 h, presenting the optimal condition for solution treatment of the alloy. The microstructural examinations revealed three different precipitates consisting of CaMgSi, Ca2Mg6Zn3, and Mg2Si in the solid solution specimens. It was found that the highest peak hardness and strength are obtained by aging the alloy at 150 °C for 16 h. This condition was confirmed by differential scanning calorimetry (DSC) tests performed on the solid solution and aged specimens. 相似文献
12.
S. Heilgeist B. Heine M. Merkel L. Hitzler Z. Javanbakht A. Öchsner 《Materialwissenschaft und Werkstofftechnik》2019,50(5):546-552
To improve the mechanical properties of cast aluminium alloys several post‐heat treatments are known. However, these treatments cannot directly be transposed to additively via selective laser melting manufactured aluminium alloys, e. g., aluminium‐silicon‐magnesium (AlSi10Mg). Therefore, this study aims to determine suitable post‐heat treatments to optimise the mechanical properties of SLM‐built AlSi10Mg specimen. The influence of various post‐heat treatment conditions on the material characteristics was examined through hardness and tensile tests. The findings indicate that the Vickers hardness and ultimate tensile strength could not be improved via secondary precipitation hardening, whereas the fracture elongation shows a value which is distinctly higher than the values of a comparable cast alloy. Solution annealing at 525 °C reduces the hardness and the ultimate tensile strength by about 40 % and increases the fracture elongation three times. A subsequent precipitation hardening allows recovery of 80 % of the as‐built hardness, and 90 % of the previous ultimate tensile strength combined with maintaining an improved fracture elongation of about 35 % compared to the respective as‐fabricated condition. 相似文献
13.
This paper presents an experimental research carried out for testing the simple calculation models presented in EN 1993‐1‐2 for the determination of the fire resistance of steel structures, as well as the models for calculating the development of temperature in the structure. The analysis was carried out for the simple heat transfer models in protected and unprotected steel elements, for the basic parameters of reduction of mechanical properties of steel at high temperatures, and for simple calculation models for determining fire resistance of elements subjected to vertical force in combination with and without the action of the axial force. 相似文献
14.
S. Yu L.X. Du C.X. Yao R.D.K. Misra B. Zhang 《Materialwissenschaft und Werkstofftechnik》2019,50(10):1221-1231
The effect of prior austenite on reversed austenite stability and mechanical properties of Fe‐0.06C‐0.2Si‐5.5Mn‐0.4Cr (wt.%) annealed steels was elucidated. With the decrease of austenitizing temperature from 1250 °C to 980 °C, the prior austenite changed from complete recrystallization to partial recrystallization, and the average austenite size was reduced. The volume fraction of reversed austenite was increased from 26.32 % to 30.25 % because of high density of grain boundaries and dislocations. The martensite transformation temperature of annealed steels was increased from ～115 °C to ～150 °C, and both of thermal and mechanical stability of reversed were reduced. There was no significant different in tensile properties, however, the impact toughness was enhanced from 100 J to 180 J at ?60 °C. The excellent impact toughness in annealed steel (austenitized at 980 °C) was obtained because of higher density of high misorientation grain boundaries, more volume fraction of reversed austenite and reduced segregation at grain boundaries. 相似文献
15.
D. Răducanu V.D. Cojocaru N. Șerban C. Trişcă‐Rusu M.G. Necula R.A. Mudrac I. Dan A. Nocivin I. Cinca 《Materialwissenschaft und Werkstofftechnik》2019,50(5):553-564
Magnesium alloys are used for degradable orthopaedic and cardiovascular implants due to their favourable mechanical and biological properties, degradation ability in physiological environment and stimulatory effect on the new bone formation. The research challenges are related to the increase of biological and mechanical compatibility. For the present study, a magnesium based alloy design was conducted to the following chemical composition: Mg?2.7Zn?1Ca?0.6Zr (wt.%). A complex thermomechanical processing route was applied: a plastic deformation by extrusion at various temperatures and deformation degrees (400 °C–480 °C, ? = 20 %–40 %), followed by various final heat treatments at 200 °C–400 °C for 10 min–60 min. Further, the influence of processing parameters upon the structure, mechanical properties and biological response was studied. Processed specimens were characterized by scanning electron microscopy (secondary electron imaging and energy dispersive spectroscopy) and mechanically by tensile tests. The most representative results were obtained for the samples extruded at 450 °C/? = 20 %, followed by a final heat treatment at 350 °C/15 min, air cooling. Further, for samples which revealed promising results, in‐vitro testing was developed. Biocompatibility testing of the Mg?2.7Zn?1Ca?0.6Zr (wt.%) alloy was realized by indirect contact studies using the Vero (ATCC® CCL‐81?, American Type Culture Collection) cell line. Cells morphologies, cell viability and proliferation were evaluated. 相似文献
16.
M. Hussain Y. Nawab Z. Rizwan A. Mumtaz A. Basit 《Materialwissenschaft und Werkstofftechnik》2018,49(2):206-209
Contrary to normal materials, the auxetic/meta‐materials expand transversally as well as longitudinally when subjected to longitudinal load and contract in both directions on compression. In this work, auxeticity is obtained in composites reinforced with carbon woven fabrics placed at certain angles. The auxetic effect on the mechanical properties of the prepared carbon/epoxy composites was investigated. The mechanical properties include the tensile, flexural and impact properties. It is found that the tensile properties are not affected by the auxetic effect; however, the flexural and impact properties are significantly enhanced by the auxetic effect. 相似文献
17.
S. Wang Y. Liu C.J. Wu J.H. Wang X.P. Su 《Materialwissenschaft und Werkstofftechnik》2019,50(7):810-818
In order to understand the effect of boron on the microstructure and mechanical properties of eutectic aluminum‐silicon alloy modified with phosphorus, complex modification of eutectic aluminum‐silicon alloy by aluminum‐3phosphorus and aluminum‐3boron was conducted. The results show that the area fraction of primary α‐aluminum in eutectic aluminum‐silicon alloy modified with aluminum‐3phosphorus increased first and then decreased with increasing amounts of aluminum‐3boron. The area fraction and the size of primary silicon decreased rapidly first and then stabilized. The morphology of eutectic silicon transformed from needle‐like into fine short rods or granules after complex modification with aluminum‐3phosphorus and aluminum‐3boron. The ultimate tensile strength of the alloy modified with 0.4 wt.% aluminum‐3phosphorus and 0.2 wt.% aluminum‐3boron increased by 18 %, compared with that of the eutectic aluminum‐silicon alloy modified with aluminum‐3phosphorus, while the elongation decreased by 5 %. It was concluded that the comprehensive mechanical properties of eutectic aluminum‐silicon alloy were improved. 相似文献
18.
K. Tushtev J. Horvath D. Koch G. Grathwohl 《Materialwissenschaft und Werkstofftechnik》2004,35(3):143-150
Failure Behavior of Fiber Reinforced Ceramics with Porous Matrix – Experiments and Modeling A 2D reinforced carbon/carbon‐composite was investigated in tensile tests with variable fiber orientation relative to the loading direction. The experimentel results from the 0° ‐ and 45° ‐ tests allow the derivation of material parameters to be implemented into a macroscopic model describing the materials response under quasi‐static loading conditions. The model is based on the damaging concept and plasticity theory and is used to predict strength and elastic constants of the composite under variable angles between fiber orientation and loading direction. The predicted data are confirmed by experimental results. 相似文献
19.
G.M. Gençer N. Öztoprak H.T. Serindağ 《Materialwissenschaft und Werkstofftechnik》2018,49(9):1059-1067
In this paper, the effects of post‐weld heat treatment on modification of microstructures and mechanical properties of friction stir welded and gas metal arc welded AA6061‐O plates were compared with each other. Gas metal arc welding and friction stir welding were used as the applicable welding processes for AA6061‐O alloys. The applied post‐weld heat treatment consisted of solution heat treatment, followed by water quenching and finally artificial aging. The samples were classified as post‐weld heat treated and as‐welded joints. The microstructural evolution, tensile properties, hardness features and fracture surfaces of both as‐welded and post‐weld heat treated samples were reported. The results clearly showed that friction stir welding process demonstrated better and more consistent mechanical properties by comparison with the gas metal arc welding process. The weld region of as‐welded samples exhibited a higher hardness value of 80 HV0.1 compared to the base material. In addition, the feasibility of post‐weld heat treatment in order to enhance the mechanical properties and to obtain more homogeneous microstructure of 6061‐O aluminum alloys was evaluated. 相似文献
20.
The application of carbon nanotubes as the reinforcing phase in composite materials is considered. A literature review in regards to the simulation approaches that have been done in order to study the behavior of nanotube‐reinforced composites from several aspects is provided. After that, a new approach for investigating the mechanical properties of the composites reinforced with randomly oriented fibers using the finite element method is proposed. The main idea is to create regular shaped islands around the distributed fibers and to connect these islands to each other and to the representative volume element. Two application examples show the flexibility and the reliability of the proposed method. It has been shown that this approach can handle both aligned and arbitrary distributions of the nanotubes. 相似文献